Analysis of microstrip discontinuities by the method of integral equations for overlapping regions

The method of integral equations for overlapping regions (MIEOR) in conjunction with a planar dispersive waveguide model is proposed for the investigation of microstrip discontinuity problems. A general formulation for a microstrip multiport junction and the numerical solution for the scattering matrix of T- and right-angled bend junctions with and without matching stubs are presented. The proposed technique directly leads to Fredholm´s integral equation of the second kind or a coupled set of integral equations for the electric field components defined in overlapping subregions of the planar dispersive waveguide model. The Galerkin´s method is employed to find the unknown coefficients in the electric field series expansion which represent the S-parameters of the junctions. The mathematical substantiation of the algorithm is provided. Numerical results are presented for T- and right-angled microstrip junctions showing good agreement with results already published